The present invention concerns media for separations that involve partition of a desired substance or group of substances between a polymer and a liquid. The polymers used are normally called separation media and may be soluble or insoluble in the liquid. For the separation of biomolecules the liquid is often aqueous. According to the inventive concept, the polymer is a hydrophilic poly(vinyl ether).
Typically, insoluble separation media are based on hydrophilic porous matrixes built up of a synthetic polymer or a biopolymer, for instance poly(hydroxyalkyl methacrylate), dextran or agarose. The matrixes have been in form of beads, particles or monoliths (continuous forms). Often the surface of the matrix has been modified with a specific functionality in order to provide the actual interaction between solute molecules and ligands immobilised on the matrix.
Today, ion exchange is the most frequently used chromatographic technique for the separation of biomolecules. Other important techniques are gel filtration, hydrophobic interaction, reversed phase, metal chelate chromatography, covalent chromatography, and affinity chromatography. For a review se J-C. Janson et al.sup.1). The adsorption principles of these techniques have also been applied to other separation methodologies, for instance batch procedures, electrophoresis, centrifugation, etc.
Vinyl ethers have been suggested as monomers in radical polymerizations in order to synthesize chromatographic support particles.sup.16,17). However, vinyl ethers are not susceptible to radical polymerization, which indicates that poly (vinyl ethers) are not enabled from this type of publications.
Poly(vinyl alcohols) are prepared by radical polymerization of vinyl acetate with subsequent ester hydrolysis. Due to hydrogen radical abstraction and head to head polymerization a significant amount of unstable/destabilized configurations such as vicinal diols and carbon--carbon branchings [--CH.sub.3-n (--C (-).sub.3).sub.n, where n is 2 or 3] will be introduced.
The synthesis of essentially linear poly(vinyl ethers) containing a low number of vinyl ether subunits by living cationic polymerization has previously been described.sup.18-21) for alkyl vinyl ether, 2-acetoxyethyl vinyl ether, 2-hydroxyethyl vinyl ether, 2-aminoethyl vinyl ether, 3-dikarboxypropyl vinyl ether and esters and amides thereof, 2-carboxyethyl vinyl ether etc. See also citations made in refs. 18-21. The publications discuss the amphiphilic properties of the oligomers.
Living cationic polymerization of ethyl 2-(vinyloxy)ethoxy-acetate with subsequent hydrolysis of pendant ester groups has enabled linear poly(vinyl ethers) containing a high number of vinyl ether subunits. The pendant group in the final polymer has uniformly been --OCH.sub.2 CH.sub.2 OCH.sub.2 COOH.sup.22).